1. Field of the Invention
This invention relates generally to a method and apparatus useful in the exploration of subterranean regions and, more particularly, to a method and apparatus useful in the exploration for, and production of, hydrocarbons from subterranean regions. In various aspects, the present invention relates to a method and apparatus for creating a bore-hole log, a bore-hole video log, a digital bore-hole video log that uses less memory than conventional digital video, and/or for associating digital audio information with a digital bore-hole video log.
2. Description of the Related Art
The visual analysis of well-bores can provide useful information regarding the stratification, fracturing, and layering of various geological formations. The more detailed the visual analysis, the better the ability to characterize a given formation.
Data-gathering, including video and audio data-gathering, of wells can be accomplished by utilizing wireline logs and/or logging-while-drilling (LWD) tools to obtain certain physical characteristics of a formation. Wireline logs require an umbilical (i.e., a wireline) from the surface to provide electrical power and are generally utilized after a well has been drilled. Logging-while-drilling (LWD) tools are used to provide real-time analysis of subsurface formations during the actual drilling operation. Logging-while-drilling (LWD) tools typically include their own power source as the LWD tool string is an integral part of the bottom home assembly and it would be impractical to connect an umbilical from the surface to provide electrical power and/or other requirements of the various LWD tools.
There have been attempts in the prior art to provide visual analysis of a bore-hole. For example, U.S. Pat. No. 4,463,378, issued Jul. 31, 1984, to Rambow, discloses a display system for use with a well logging tool of the type that scans a bore-hole wall by rotating an acoustic transducer while emitting and receiving acoustic energy. The received acoustic or information signals are received and recorded for later use.
U.S. Pat. No. 4,774,573, issued Sep. 27, 1988, to Mount et al., discloses an apparatus for creating a video display from information generated by acoustically scanning a reflecting boundary circumferential bore-hole.
U.S. Pat. No. 4,855,820, issued Aug. 8, 1989, to Barbour, discloses an apparatus and method of visually examining the sidewalls of a bore-hole. The apparatus includes a wide-angle video camera, power supply/triplexer, a telemetry board, an FM modulator video amplifier transmission board, gyroscope data interface board, and a gyroscope for showing the directional orientation of the camera. The orientation and video images are transmitted to a video display monitor on the surface and recorded by a video cassette recorder for a permanent record.
U.S. Pat. No. 5,134,471, issued Jul. 28, 1992, to Gendron et al., discloses a bore-hole camera monitoring system comprising a camera head assembly adapted to be lowered into a bore-hole with the control unit for operating the camera located above ground. The camera head assembly of the '471 device includes a fixed portion and a rotary portion. The fixed portion of the camera head assembly of the '471 device comprises a microcontroller for controlling the operation of the camera, a position encoder for detecting the angular rotation of the camera with respect to the fixed portion of the camera head assembly, and a communication interface including means for multiplexing the video signal generated by the camera. The control unit of the '471 device comprises a computer, a video monitor, and a communication interface. In addition, a depth counter is connected to the computer.
U.S. Pat. No. 5,140,319, issued Aug. 18, 1992, to Riordan, discloses an instrument probe containing a video camera and light source with the power source located at the surface. A support cable contains an optical fiber for conducting camera signals to the surface and conducting power to the instrument.
However, in spite of these advances in the prior art, there is still a need for a method and apparatus to create a visual well-bore log that does not suffer from one or more of the deficiencies of the prior art, deficiencies such as the large memory and/or storage requirements for conventional video logs and/or the inefficient incorporation of digital audio data with a digital video log. There is, thus, a need in the art for a method and apparatus to create a digital video log that utilizes less memory and/or storage capacity than conventional video logs, while providing more relevant information than that provided by conventional video logs. There is also an additional need in the art for an efficient way to incorporate digital audio data with a digital video log.
These and other needs in the art will become apparent to those of skill in the art upon review of this specification, including the drawings and claims.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.